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Flashcards in Growth And Development Of The Skull Deck (24)
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1
Q

What are the two types of ossification of the skull

A

Intramembranous - mesenchymal cells differentiate into osteaoblasts which secrete osteoid and cells called osteocytes form when trapped ossify during fetal period and starts at the centre and ossifies outwards

Endochondral - cartilage model artery through bone impregnates Cartilage with calcium primary and secondary centres

2
Q

Where does each of the ossifications of the skull occur

A

Intramembranous ossification

  • flat bones of skull
  • parietal frontal
  • Easily modified by environmental factors (hydrocephaly)

Endochondral ossification

  • bones of the base of the skull
  • more complex
  • ethmoid and sphenoid
  • Tight genetic control
  • deformity is achondroplasia
3
Q

Which sinus is absent at birth

A

Frontal sinus

4
Q

What is hydrocephaly

A

Water on the brain
Brain grows in cav like balloon
Increasing brain volume = lifts membrane bones apart applying tension to the sutures

5
Q

When is the cranial growth depicted

A

Dictated in-utero

6
Q

Why is the brain ~25% formed at birth

A

To perform essential protective qualities for life such as suckling and coughing

7
Q

What is special about fontanelles

A

Soft spots which is a gap where no bone has been developed yet
Anteriofontanelle
Can move and moulded during giving birth to help mother

8
Q

What does the neonate minimal development have as a positive

A

Non essential parts are not fully formed so the neonate has small jaws and nose
This all has to do with the compromise of giving birth compromise

9
Q

Where are both of the fontanelles and when does one close

A

Anterior and posterior, posterolateral fontanelle

Anterior closes at ~18 months

10
Q

What is an eminence

A

Bone that protrudes slightly frontal and parietal

Converted of ossification

11
Q

How can a baby not hold up its head

A

Structures such as mastoid process not fully developed so postural muscles such as scm cannot support neck as muscle is unsupported

12
Q

What is the difference between the pelvic inlet and outlet

A

Inlet - transverse diameter > AP diameter

Outlet - transverse diameter

13
Q

What’s it the ratio of skull:face for a neonate and adult

A

Neonate - 8:1

Adult - 2.5:1

14
Q

What influences the growth of the jaw

A

The development and eruption of teeth

Wisdoms don’t

15
Q

How are various processes of the skull formed

A

As muscles attach to bones pull on them developing processes

16
Q

What kind of hormones influence skull growth

A

Sex hormones
Males - bulkier stronger skull
Female - tensile and delicate

17
Q

What does the primary cartilaginous joint allow

A

Synchondroses

In base of skull allow face to be carried forward as it grows

18
Q

What are the two synchondroses of the skull

A

Spheno-ethmoidal synchondrosis close at 6

Spheno-occipital activated at birth and close at 25

19
Q

How is the adult skull light

A
Lightness optimised by 
Diploe
Orbits 
Cavities 
Paranasal sinuses
20
Q

What are the paranasal sinuses

A
Air filled spaces 
Maxilla 
Sphenoid 
Frontal 
Ethmoid
21
Q

How is the adult skull strong

A

Near spherical shape
Suture joints crack stoppers
Has a crumple zone and incorps Le fort fractures and buttress syst

22
Q

What is diploe

A

Sandwich
Has outer and inner compact bone
And light cancellous centre which is the diploe

This is light and strong
Many holes filled with fatty marrow
Shock absorber

23
Q

What are the endentulous changes

A

Alveolar processes resorb from the maxilla and mandible due to loss of teeth

24
Q

What are the three conformational changes of the skull

A

Neonate - before birth and of small infant
Adult - usual
Old age - may end up Edentulous